1. The Field of the Invention
The present invention relates to valves, and, in particular, relates to hemostasis valves.
2. Relevant Technology
Several current surgical procedures require temporary and often repeated introduction and removal of catheters and/or guidewires within the cardiovascular system of a patient. For example, using only a relatively small incision, a catheter can be introduced into the body of a patient and used to deliver a fluid, such as a medication, directly to a predetermined location within the cardiovascular system. Catheters can also be used for exploratory surgery and for removing tissue samples within a patient's body. One increasingly common use for catheters is in the placement of small balloons that can be selectively inflated within a blood vessel. The balloons are used for opening blood vessels that have been blocked or partially blocked by fat build-up. This opening or altering of the vein is referred to as angioplasty.
A common catheter design used in performing many of the procedures includes an elongated, flexible, cylindrical catheter body having a fluid flow passageway or a lumen extending along the interior of that catheter body. During one type of use, an end of the catheter is inserted into the body of the patient through an incision in a blood vessel in the cardiovascular system. The catheter is advanced along the internal passageway of the vessel until the end of the catheter is located at a desired predetermined location for conducting an intended activity.
A guidewire is a long, cylindrical, flexible wire that is commonly used for directing the catheter to the desired location within the body. A guidewire is typically smaller in diameter and more rigid than a catheter. It is, therefore, easier for a surgeon to first direct and advance a guidewire within the cardiovascular system to the desired location within the body of the patient. The opposing end of the guidewire, positioned outside the body of the patient, is then received within the lumen of the catheter. Using the guidewire as a guide, the catheter is advanced along the length of the guidewire so as to properly position the catheter within the body of the patient. If desired the guidewire can then be removed from within the catheter to open the lumen of the catheter. In an alternative process for inserting the catheter, the guidewire is initially received within the lumen of the catheter and the catheter and guidewire are simultaneously advanced within the cardiovascular system of the patient.
Operations using catheters can often require the insertion and removal of several different types of catheters and guidewires. One of the problems encountered with the insertion and removal of catheters and guidewires is controlling bleeding at the point where the catheters and guidewires are first introduced into the cardiovascular system.
In one approach to controlling bleeding and ensuring easy insertion and removal of the catheter and/or guidewire within the cardiovascular system, one end of an introducer is first secured within a large vein of a patient. An introducer is a relatively large, hollow tube. The opposite end of the introducer is positioned outside the body of the patient and is attached to an adapter.
An adapter typically comprises a short, rigid tube having a passageway extending therethrough. Attached at one end of the adapter tube is a connector. The connector is used to connect the passageway of the adapter to the exposed end of the introducer. This enables fluids and/or medical instruments, such as catheters and guidewires, to pass between the adaptor and the introducer.
Positioned at the opposite end of the adaptor tube, is a valve commonly referred to as a hemostasis valve. The hemostasis valve includes an enlarged chamber portion at the end of the adaptor remote from the patient. The chamber is aligned with and is connected to the passageway extending through the adaptor.
Positioned within the chamber is some type of seal. The adaptor may have more than one seal disposed therein. During use of the adaptor, the pressure of the blood of the patient caused by the beating of their heart can cause blood from the patient to flow up through the introducer and into the passageway of the adaptor tube. The one or more seals, which either independently close or are compressed around the catheter or guidewire, prevent blood from escaping out of the adaptor through the access of the valve.
Various seal arrangements are available with different types of hemostasis valves ranging from one seal to a plurality of seals. One of the main purposes of the valve arrangement is to be able to block off the passage way to prevent the loss of bodily fluids through the hemostasis valve. One type of seal that has been used in hemostasis valves is a soft, cylindrical, compressible seal. The compressible seal has a passageway extending along the length of the seal. The seal is oriented in the chamber so that the passageway through the seal is aligned with and connected to the passage in the adaptor tube.
To seal a hemostasis valve incorporating a compressible seal around an inserted catheter or guidewire, a portion of the hemostasis valve is advanced, which in turn compresses the seal within the chamber, causing the passageway in the compressible seal to constrict. If the shaft is advanced sufficiently far within the chamber, the passageway in the seal constricts so as to form a seal around the exterior surface of the catheter or guidewire positioned in the passageway. Alternatively, if the catheter or guidewire is removed from within the seal, the passageway in the seal can constrict in response to compressive force so that the seal completely closes off the access through the valve.
When a single compressible seal is used, there tends to be a loss of bodily fluid from the patient, especially when the catheter or guidewire is removed. A single seal is more prone to resulting in needless blood loss and increases the risk of contamination of the blood of the patient. Furthermore, the leakage of bodily fluids such as blood may produce a messy and slippery work environment for the surgeon. With the increasing number of blood transmitted diseases, such as AIDS, blood leakage from the adaptor greatly increases the risk to the surgeon and other medical personnel.
Attempts have been made to solve the leakage problem by making hemostasis valves that utilize two or more seals. Typical seals include duck-bill valves and slit valves. While multiple seals in the hemostasis valve are useful in helping to reduce the loss of body fluids, including blood, several problems still exist. Current hemostasis valves, regardless of whether the valve has one or two seals, generally have an open position and a closed or sealed position. Once the hemostasis valve has been closed, the surgeon is not able to move or reposition the catheter or guidewire without putting the hemostasis valve into the open position; however, this can permit body fluids to escape through the valve. For example, if the valve utilizes a compressible seal, the catheter or guidewire cannot be repositioned or removed unless substantially all of the compressive force is removed from the compressible seal. Once the compressive force is removed, the hemostasis valve is no longer able to properly seal. Thus, conventional hemostasis valves are unable to provide a seal against the loss of bodily fluids while still allowing the catheter or guidewire within the valve to be repositioned.
An additional problem with existing hemostasis valves is that the seals, and in particular those seals that are compressed to form a seal, tend to exert a force upon the catheter or guidewire. The forces, including the frictional forces acting on the instrument, are commonly referred to as "drag". The drag acting on the catheter or guidewire disposed in a seal makes it difficult for the surgeon to be able to adjust the catheter or guidewire. In particular, the drag reduces the ability to adjust the catheter or guidewire by the "feel" of the movement. Conventional hemostasis valves must be adjusted to remove the compressive forces acting on the seal. However, removing the compressive forces acting on the seal can result in fluid leakage as discussed above.
Finally, having to first remove the compressive force, then reposition or remove the catheter or guidewire, and finally readjust the hemostasis valve to compress the seal so as to form a seal is time consuming and in turn unnecessarily lengthens the procedure.
It will be desirable to have a hemostasis valve that includes one or more seals that is able to accommodate both large and small diameter catheters and guidewires, is able to minimize blood leakage from the hemostasis valve and remain sealed while allowing the catheter or guidewire to be repositioned without the loss of bodily fluids or blood. It would also be advantageous to have a hemostasis valve in which the seal will remain sealed but which will allow an instrument such as a catheter or guidewire to be longitudinally repositioned without exerting so much drag on the catheter or the guidewire that the surgeon is unable to have a feel for the movement of the guidewire or catheter.
Such improved hemostasis are disclosed and claimed herein.